1. Field of the Invention
The present invention relates to a display controlling device and related method, and more particularly, to a display controlling device capable of displaying multi-windows and related method.
2. Description of the Prior Art
Due to the variety of scanning modes and displaying standards, a display controlling device often displays video fields after de-interlaced and scaled.
FIG. 1 is a functional block diagram of a display controlling device 10 according to the prior art. The display controlling device 10 stores received video fields in a field buffer 12, and outputs the stored video fields line by line to a line buffer 14. A de-interlacing device 16 de-interlaces scan lines stored in the line buffer 14. A scaling device 18 scales de-interlaced lines by the de-interlacing device 16. Video fields that have been de-interlaced and scaled are displayed on a display device 20.
Under consumer demand that a display controlling device should have more powerful display functions such as picture-in-picture (PIP) or picture-on-picture functions, the display controlling device 10, which can only display a single window, cannot succeed in the rapidly developing market.
FIG. 2 is a functional block diagram of another display controlling device 30 according to the prior art. The display controlling device 30 has the capability to display multi-windows. In order to display two windows at the same time, the display controlling device 30 requires two field buffers 12, two line buffers 14, two de-interlacing devices 16, and two scaling devices 18, so as to store, de-interlace, and scale a first video field and a second video field, independently. A mixer 32 mixes de-interlaced and scaled scan lines of the first video fields and the second video fields. The display device 20 displays mixed lines of the first video fields and the second video fields to display multi-windows.
Although the display controlling device 30 is capable of displaying multi-windows, the display controlling device 30 is expensive, since the prior art requires two independent sets of complicated and expensive de-interlacing devices 16 and scaling devices 18. Moreover, in order to display a third window, the display controlling device 30 further requires another de-interlacing device 16 and scaling device 18, and so, costs more.